ALSA: usb-audio: fixing upper volume limit for RME Babyface Pro routing crosspoints

In my initial patch, these were set too low.

Fixes: 3e8f3bd0 ("ALSA: usb-audio: RME Babyface Pro mixer patch")
Signed-off-by: Thomas Ebeling <penguins@bollie.de>
Link: https://lore.kernel.org/r/20200515114556.vtspnonzvp4xp44m@bollie.ca9.euSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_quirks.c

@@ -2191,7 +2191,7 @@ static int snd_rme_controls_create(struct usb_mixer_interface *mixer)
  * These devices exposes a couple of DSP functions via request to EP0.
  * Switches are available via control registers, while routing is controlled
  * by controlling the volume on each possible crossing point.
- * Volume control is linear, from -inf (dec. 0) to +6dB (dec. 46341) with
+ * Volume control is linear, from -inf (dec. 0) to +6dB (dec. 65536) with
  * 0dB being at dec. 32768.
  */
 enum {
@@ -2220,7 +2220,7 @@ enum {
 #define SND_BBFPRO_MIXER_VAL_MASK 0x3ffff
 #define SND_BBFPRO_MIXER_VAL_SHIFT 9
 #define SND_BBFPRO_MIXER_VAL_MIN 0 // -inf
-#define SND_BBFPRO_MIXER_VAL_MAX 46341 // +6dB
+#define SND_BBFPRO_MIXER_VAL_MAX 65536 // +6dB
 
 #define SND_BBFPRO_USBREQ_CTL_REG1 0x10
 #define SND_BBFPRO_USBREQ_CTL_REG2 0x17